Talking about the paper inspection of carton

The carton factory shall carry out the inspection of the purchased base paper according to the requirements for the implementation of the base paper procurement plan, so as to confirm whether the quantity and quality thereof comply with the stipulations. The first purpose of the inspection is to prevent substandard papers from entering the factory, minimize the losses caused by the original paper during production, and secondly, check and understand the performance of the base paper to make a correct choice, minimize the cost and ensure the quality of the finished product.

The inspection of the base paper follows the following process:

The first is to verify whether the delivery code is the same as the purchase plan and whether the arrival quantity is the same as the delivery code. The type, labeling quantity, specifications, and number of pieces of the base paper can be confirmed on the spot. The weight can be weighed by the division scale, and the deviation must be controlled within ±3 inches (three-thousandths of an inch). Deficiency should be deducted.

Second, check whether the label of the roll paper is clear, whether the packaging is defaced, and whether the base paper is damaged or damp. If it is damaged or damp, it should be deducted. The specific method is as follows: If damage or moisture occurs on the side of the roll paper, count from the outside to the inside without damage and moisture, for example, N = 32 layers (the 33rd layer is not damaged, damp), and then measure The distance D from the 16th floor to the axis, for example, D=0.55m, combined with the size L of the roll paper (unit: meters) and the basis weight G (unit: g/m2), the weight to be deducted is W=10- 3G×L×(2×3.14×D)×N (unit: kg). If damage or moisture occurs on the end face of the roll paper, it is generally not allowed to exceed 2 cm, otherwise it will be handled as a return.

Third, check whether there is a sign on the end surface of the roll paper joint, whether the end surface of the roll paper is flush with the shaft core, whether the core of the roll paper core has a core phenomenon, whether the two end surfaces of the roll paper have the same diameter, and the rewinder is tight. Degree and whether the two ends are elastic, whether the binding of the roll paper meets the standard, whether there is a color difference in the batch of rolls, and so on.

Fourth, check the moisture content of the roll paper with a pin-type moisture meter. Sampling according to GB13024-2003 and GB13023-1997. The test was performed on both ends of the roll paper, and three reference points were evenly taken. The depth of insertion was not less than 0.6 cm. Take the average of the six points tested as the moisture content of the roll paper. In the raw paper supply contract, the delivery moisture is generally specified, for example (8.0 ± 2.0)%. The tested roll paper moisture content is qualified within the scope of delivery moisture, otherwise it is treated according to the agreement of both parties, and the excess water must generally be deducted. The specific method is as follows: If the moisture content of the roll paper M1 exceeds the upper limit of delivery moisture Ma, the weight of the roll paper is W, the weight to be deducted is W×(M1Ma)/Ma; if the moisture content of the roll paper M1 is lower than the lower limit of delivery moisture Mb Roll paper must be on-line trial, does not affect the normal production and quality of finished products according to qualified processing, or return. It is worth mentioning that the moisture content of the test roll paper is carried out when the roll paper is accepted into the factory. When the workshop is used, it needs to follow-up on the spot, that is, quality tracking, and find out the problems in a timely manner and contact the supplier to solve.

Fifth, the performance test of the base paper. Since the general carton factory does not have the conditions for temperature-controlled room testing and the timeliness of the inspection is taken into consideration, normal testing should be adopted. As long as there is no obvious defect on the surface of the roll paper, it can be sampled in the second layer, and the technical indicators such as the quantitative, ring crush strength, burst strength, crack length, and water absorption can be measured according to the methods proposed by relevant national standards. Quantitative test is mainly to see if there is overweight or insufficient weight; the most critical of the ring pressure strength and burst strength test, the test results using regression analysis (see the article "The effect of moisture content on the strength of corrugated board"), and then refer to The two sides agreed that you can know whether it is qualified; the test crack length is mainly to understand the tensile strength of the base paper, which can be used as the main basis for the application of tile line; water absorption determines the adhesive properties of the base paper, printing performance, atmospheric moisture impact The degree of intensity, and so on. Other aspects, such as tightness, smoothness, folding resistance, flat compressive strength, oil permeability, etc., are determined according to specific needs.

Finally, carefully record each batch of paper inspection results, analyze and compare, and retain excellent suppliers (quality, price, and timely delivery), and remove unqualified suppliers from the supplier list. The inspection result of the base paper is used as an important reference in the configuration of the base paper of the line board.

Here, another method of testing quantitation with a crush strength test specimen without a quantitative sampler is described.

Because the size of the ring-crush test specimen is longitudinal × transverse = 15.2 cm × 1.27 cm, its area is 19.304 cm2, and the total area of ​​the 5 ring-compression specimens is 96.52 cm2, so the N-ring crush strength test specimens are weighed. The total mass M, which is converted into the mass of five samples of ring crush strength, is first increased by 100 times and then divided by 0.9652 to obtain the basis weight W of the base paper.

For example, if the total mass of 10 crush strength test pieces is M=2.89 g, then the basis weight of the base paper is W=100 M/(2×0.9652)=149.7 g/m 2, ie, 150 g/m 2. Again, if the total mass of 8 samples of ring crush strength is measured to be M=3.84 g, then the basis weight of the base paper is W=100 M×5/(8×0.9652)=248.7 g/m 2, ie, 249 g/m 2. This test method is particularly suitable for the quantification and strength testing of smaller samples.

Tips for quantitative inspection of raw paper

Quantification of paper and board (also known as grammage, g/m2) is a basic technical indicator. General enterprises will be equipped with a quantitative sampler, take 10 round paper samples with an area of ​​100cm2, and weigh them in order, and calculate the quantitative value through the formula. There are still some companies that directly use a paper cutter to take a 10×10cm2 square pattern for weighing. There will be relatively large errors, which cannot guarantee the authoritativeness of the test results, and may cause unnecessary problems between papermaking companies and carton enterprises. contradiction. Without a dedicated quantitative sampler is not a big problem, because many companies now have a ring pressure test sampler, it can completely replace the quantitative sampler work, both quantitative and loop pressure tests can be done. The specific method of operation is as follows:

110g electronic balance with a maximum weighing accuracy of 0.01g

Eight pieces are equally spaced longitudinally on a single pattern. The area of ​​each sample is 15.2 x 1.25 cm2. The area of ​​8 samples is 15.2 x 10 cm2. Eight samples are weighed together and the weight is divided by 1.52. Multiplied by 100, you get a quantitative value.

Reprinted from: Light Industry Information Network